cold-blooded
Americanadjective
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designating or pertaining to animals, as fishes and reptiles, whose blood temperature ranges from the freezing point upward, in accordance with the temperature of the surrounding medium; poikilothermic.
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without emotion or feeling; dispassionate; cruel.
a cold-blooded murder.
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sensitive to cold.
adjective
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having or showing a lack of feeling or pity
a cold-blooded killing
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informal particularly sensitive to cold
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Technical term: poikilothermic. (of all animals except birds and mammals) having a body temperature that varies with that of the surroundings
Other Word Forms
- cold-bloodedly adverb
- cold-bloodedness noun
Etymology
Origin of cold-blooded
First recorded in 1585–95
Compare meaning
How does cold-blooded compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
A cold-blooded animal has a body temperature that varies along with the outdoor temperature, and a cold-blooded person is someone who seems to feel no emotions. Your pet lizard may love you, but she's still cold-blooded. During a hot, sunny day, a cold-blooded animal like a snake experiences a rise in body temperature, which it can only moderate by finding a shady spot to hide. When the sun goes down at night, a snake's body temperature falls. Cold-blooded people, on the other hand, regulate their body temperature even when it's chilly outside, like other warm-blooded animals. They're cruel and unfeeling, though. This meaning comes from the old-fashioned belief that blood temperature rises with emotion.
Vocabulary lists containing cold-blooded
Idioms and Expressions, List 3
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Talk Like Shakespeare Day, List 1
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Long Way Down
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"Insects are cold-blooded, so they are at the mercy of external temperatures," said Northwestern's Marco Gallio, who led the study.
From Science Daily • Mar. 26, 2026
They were cold-blooded, for one thing, and probably resembled lizards.
From The Wall Street Journal • Feb. 10, 2026
But there’s a biological reason: Sea turtles are cold-blooded, and don’t heal as fast as creatures with warm blood pumping through their veins.
From Los Angeles Times • Jan. 28, 2026
Writer-director Alex Scharfman makes a worthy attempt at sketching the Leopolds as a parodic version of the real-life Sackler family, but never gets close to conjuring their cold-blooded, dark-hearted evil.
From Salon • Apr. 4, 2025
It was a useful reminder that all men, even the most seemingly cold-blooded, have a core of decency, and that if their heart is touched, they are capable of changing.
From "Long Walk to Freedom" by Nelson Mandela
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
